Pitch control means for variable pitch propellers



PITCH CONTROL MEANS FOR VARIABLE PITCH PROPELLERS Filed Feb. 7, 1956 April 5, 1960 1.. A. PEHRSSON 3 Sheets-Sheet l INVENTOR LEN NART ANDERS PEHRSSON BY JW. Q?

HIS ATTORNEYS April 5, 1960 L. A. PEHRSSON PITCH CONTROL MEANS FOR VARIABLE PITCH PROPELLERS 3 Sheets-Sheet 2 Filed Feb. 7, 1956 April 5, 1960 L. A. PEHRSSON 2,931,443

PITCH CONTRQL MEANS FOR VARIABLE PITCH PROPELLERS Filed Feb. 7, 1956 3 Sheets-Sheet 3 INVENTOR.

LEN NART ANDERS PEHRSSON H IS ATTORNEYS nited Stats Patent PITCH CONTROL MEANS FOR VARIABLE PITCH PROPELLERS Lennart Anders Pehrsson, Karlstad, Sweden, assignor to Ahtiebolaget Karlstads Mekaniska Werkstad, Karlstad, Sweden, a corporation of Sweden Application February 7, 1956, Serial No. 564,043

4 Claims. (Cl. 170-16032) This invention relates to controllable pitch propellers for use in the propulsion of ships, boats, and the like, and it relates more particularly to systems for controlling the pitch of such propellers.

In accordance with the present invention, a system is provided which includes a propeller having a motor therein for varying the pitch of the blades of the propeller and in which power is supplied to the motor for adjusting or varying the pitch of the blades through the end of the hub opposite from the end attached to the propeller shaft. Thus, in propellers for propulsion of ships, the power supply means is connected to the motor through the trailing or aft end of the propeller hub.

More particularly, control systems embodying the present invention are of the hydraulic type and include a hydraulic motor mounted in the hub of the propeller which is connected with and energized by a source of hydraulic pressure mounted in the hull of the ship, the connections between the motor and the source of hydraulic pressure extending into the propeller from the end remote from the propeller shaft. In the new system, the conduits for supplying hydraulic pressure to the motor may extend through the rudder post of the ship into the aft end of the propeller, or through a separate member which also serves to support the trailing end of the propeller hub or through conduits suitably arranged on the outside of such a member or the rudder post.

The new system also includes a means for indicating the pitch of the propeller and/or controlling accurately the movements of the blades in response to operation of a manual or automatic control, the indicating or follow-up means being constructed and arranged to eliminate errors in its operation which might be caused by endwise movement of the propeller as a whole by thrust or reaction thereon.

Connection of the po or supply to the pitch-control motor without utilization of connections through the propeller shaft has many advantages. Solid propeller shafts can be used instead of the more expensive hollow shafts. The solid shaft may be of smaller diameter without loss of strength. Smaller shaft bushings and packings can be used and the connections between the power source and the pitch-control motor simplified and shortened. The simplifier connections, in turn, reduce leakage or possible disabling of the control system to a minimum and also facilitate servicing, when required.

Other advantages will be apparent from the description of a typical form of the invention hereinafter.

For a better understanding of the present invention, reference may be had to the accompanying drawings in which:

Figure l tern for a variable pitch propeller of the type embodying the present invention;

Figures 2A and 2B are views in longitudinal section through the trailing portion and the leading portion, respectively, of a propeller of the type embodying the present invention;

is a schematic illustration of the control sys- Figure 3 is a view in longitudinal section through a control valve by means of which pressure is supplied to the propeller motor for varying the pitch of the propeller; and

Figure 4 is a view in cross section taken on line 4-4 of Figure 2A.

Any conventional type of hydraulically controlled variable pitch propeller may be used in the new system by suitable modification and the propeller chosen to illustrate the present invention is generally of the type disclosed in the Pehrsson et a1. U.S. Patent No. 2,794,- 508, dated June 4, 1957.

The propeller 10 includes a hub frame 12 having a plurality of circular recesses or sockets 13 in which the bases of blades 11 are rotatably mounted for rotation about axes substantially radially of said hub frame 12. Cylinders 14 and 15 are formed in the frame 12 on opposite sides of a center chamber 16, in which the actuating members for rotating the blades 11 around their axes are mounted. Each of the cylinders 14 and 15 receives the pistons 17 and 18, respectively, which are fixed to piston rods 19 and 20, respectively.

Partitions 21 and 22 are interposed between the chamber 16 and the cylinders 14 and 15 and receive slidably the piston rods 19 and 20. Sealing gaskets or rings 23 and 24 are mounted in the partitions in contact with the piston rods 19 and 20 to prevent leakage between the chamber 16 and the cylinders 14 and 15 on opposite sides of the chamber.

Each of the piston rods 19 and 20 carries an actuating member 25 and 26 having arms 25a, 25b and 250 (Figure 4) and arms 26a, 26b and 260, respectively, corresponding in number to the blades of the propeller. Each of the arms on the member 25 has transverse slot 25d in it and each of the arms on the members 26 has a transverse slot 26d in it. These slots receive eccentrically located rollers or projections 11a and 1112 on the propeller blades, as disclosed more particularly in the Pehrsson et al. Patent No. 2,794,508. Upon movement of the pistons 17 and 18 in opposite directions, the actuating members 25 and 26 are moved in opposite directions and by means of the interengaging slots 25d and 26d the rollers 11a and 11b, the blades are rotated to vary their pitch.

Projecting from the frame 12 at the right-hand end of the cylinder 15 is a hollow extension 27 having a recess 28 therein which slidablyreceives the right-hand end of the piston rod 20. A seal 29 is interposed in the extension 27 between the recess 28 and the cylinder 15 to prevent leakage of liquid, and the piston rod 20 is provided with a passage 30 which connects the chamber 16 with the recess 28 to prevent liquid from being trapped in the recess. A sleeve portion 32 is fixed to the extension 27 and receives the propeller shaft 33, the latter being secured to the sleeve 32 by means of a key 34, splines or the like, and a nut 34A to retain them in non-rotatable relation. The forward end of the frame 12 is enclosed with a streamlined housing 35 formed of metal or other suitable material.

Referring to Figure 2A, the frame 12 also includes a tubular extension 36 which is received rotatably within a bearing sleeve 37 carried by the rudder post of the ship or, as illustrated in Figure l, a support member 38 extending downwardly from the hull H of the ship. Support member 38 is rigid and supports the rear end of the propeller hub to aid in holding the propeller against lateral play or vibration.

A housing 39 encloses the rear portion of the propeller hub and extends down to a tubular portion 40 on the member 38 in which a bearing 37 is mounted. It will be evident that the bearing sleeve and a bearing liner 4!,

Fatented Apr. 5, 1960.

enemassecured to it by a screw-threaded connection 42.

A source of hydraulic pressure for moving the pitchcontrol pistons is mounted in the ship, as shown in Figure 1. It includes a reservoir 45 for hydraulic fluid and a motor driven pump 46 by means of which liquid under pressure is delivered through the conduit 47 to a control or selector valve 48 and from the valve 48 selec- V tively through the pressure supply lines 49 and 50 to-the cylinders 14 and 15 in the propeller. The system also includes a return conduit 51. from the vaive 48 to the reservoir 45 and other return conduits 52 and 53, later to be described. The fiuidpressure line 553 communicates with a passage 55 in a distribution block 56 carried at the rear of the tubular portion it on support member '33. Screws 57 passing through theextension 40 and into a reduced portion 53 on the block 56 secure the block to the member 40. The passage 55 communicates with a conduit 60 which is supported atone end by a disc 61 secured thereto and received in a somewhat larger diameter circular recess 62 in the block 56. Lateral movement of the disc relative to the block 56 is permitted by the large size of the recess 62, but the conduit 60 need not be rotatable; The conduit 69 extends into a central passage or bore 64 in the piston rod 19, the piston rod being rotatable relative to the conduit 60. A second conduit 66. telescopically receives the conduit 60 and they are held in substantially concentric relation by means of narrow spacer fins 67 on and extending lengthwise of the con-- duit 60. A' disc or ring 68 is fixed to the left-hand end of the conduit 66 and is received non-rotatably but for lateral movement in a recess 69 in the block 56.

A. sleeve 70 extending to the left from and forming a partof the piston rod 19 receives and rotatably engages the conduit 66. Spacer fins 71 are interposed between'the outer surface of the conduit 66 and a sleeve '72. which is supported by means of a needle or roller bearing '73. within the bearing sleeve 36. The above-described arrangement of the conduits 60 and 66 centers themwith respectto the hub of the propeller and enables them to move laterally with respect to the distributor block 56 and the bearing 37 if there is any slight lack of concentricity between the parts. In this way, flexing and possible breaking of the conduits 60 and 66 are avoided.

.As will be seen in Figure 2A, fluid under pressure supplied by the conduit 50 will flow through the passage 55 and the conduit 6%] into the bore 64 of the pistonrod 1 9 and-out through the passage 75 therein into the righthand end of the cylinder 14. A passage 76 also delivers liquid under pressure from the right-hand end of the cylinder 14 into the left-hand end of the cylinder 15. Under these conditions, liquid is forced out of the righthand end of the cylinder 15 and the left-hand end of the cylinder 14, inasmuch as they are connected by means of a passage 77, through'a passage 78 in the extension 70, betweenthe conduits 6i) and 66 and into the passage 79, which is connected to the conduit 49. The flow 'of liquid under pressure causes the pistons 17 and 18 to be moved away from each other, thereby varying the pitch of the blades '11 in one direction.

Pitch variation in the opposite direction is obtained by supplying hydraulic pressure by means of the selector v-alve 48 through the conduit 49, so that liquid under pressure flows into the left-hand end of the cylinder 14 and the right-hand end of the cylinder 15 through the passage 79, between the conduit 69 and the conduit 66, and passages 73 and 77. Liquid returns to the reservoir 7 from the right-hand side of the cylinder 14 and the lefth ydrostatic pressure by means of connections to be described-.- Thus; the conduit 52 communicates with an has its inner end disposed outside of the conduit 66. A

flexible packing or seal 81 connects the left-hand end of the bearing'sleeve 72 to the distributing block 56 so that liquid is confined therein and to the interior of the bearing sleeve 36. 1

A passage 84 is also provided between the chamber 16 and the space within the bearing sleeve so that liquid displaced by reciprocation of the piston rods in the chamber 16 can how out and be returned to or flow into the chamber 15 from the reservoir 45 as may be required to compensate for such displacement. Any leakage of the system is also taken'care of by means of the conduit 53 connected with a passage 85 in the support member 38 through which the other conduits 54),. 49 and 52 extend. The passage 85 communicates by means of a a substantial hydrostatic pressure in the chamber 87 and associated parts of the propeller.

The propeller also includes mechanism for causing the propeller toassume a desired pitch in proportion to displacement of a'controllever therefor. As shown in Figure 2A, the right-hand end of the piston rod 19 carries an anti-friction bearing 9-9 in which is rotatably received a coupling 91 on the end of a Bowden wire or cable 92. The inner end of the passage 64through which the. wire extends is plugged by means of a screw plug 93. The opposite end of the wire 92 is connected to one arm 94 of a bell crank 95, the latter being mounted for pivoting movement on a pivot 96 carried by a ring 97. A series of rods 98 fix the ring 97 to a ring 99 which is biased against the left-hand end of the bearing sleeve 36 on the propeller frame and thus is responsive to endwise movement of the propeller. A spring 1% bearing against a shoulder 101 on the cap 88 and against the ring 97 produces the biasing action. With this arrangement, if for any reason the propeller should shift axially relative to, the member J8, the ring 97 will move with it so that its position is unchanged with respect to the propeller as a whole.

Shiftingpmovernent of the piston 17 and the piston rod 19 will change the angular position of the bell crank and its horizontal arm 102 will move up or down, thereby moving a cable or wire 193 connected. to it up and down. As illustrated in Figure l, the cable or wire 103 is connected to a lever 164 011 the casing 195 of the selector valve 48. The lower end of the lever 164 is connected by means of a link 136' to an actuating lever 107 which is pivotally connected at about its mid-portion to the plunger 16% of the slide valve. A Bowden Wire or cable 109 connects the upper end of the arm 107 to a control lever 110 mounted in the bridge of the ship or at any other convenient position.

Both of the levers 1G4 and 197 are normally biased in a clockwise direction by means of a spring 111 interposed between the'upper arm. 1940: of the lever and a fixed iug 195a on the valve casing 165. It will be ap-.

parent that if the control lever 110, for example, is moved clockwise as viewed in Figure 1, it v ll cause counterclockwise movement of the lever 1%? around the pivot of the left-handend of the link 1&6 because the lever 104 is at that instant retained against movement by means Consequently, the slide valveplunger 108 will be moved to the left from the position shown in Fi ure 3, which is the neutral posi,

tion of the valve.- As shown, the valve casing contains a series of five chambers 115, 116, 117, 118 and 119, the chamber 115 being connected to the pressure line 47, the chambers 116 and 118 being connected to thelines 49 and 50, respectively, and the chambers 117 and 119 being connected to the line 51, which serves as a return to the reservoir 45. The slide valve plunger has a series of enlargements 120, 121 and 122 thereon which, in the position shown, serve to prevent communications between adjacent chambers in the valve. However, when the valve plunger 108 is moved to the left, liquid can flow through the pressure line 47 into the chamber 115, from the chamber 115 into the chamber 116 and through the pressure line 49, passage 79, conduit 66, passages 78 and 77 into the cylinders to cause the pistons 17 and 18 to move toward each other. The liquid under pressure discharged through the conduit 60 flows through the conduit 50 into the chambers 118 and 117 of the valve and through the return line 51 to the reservoir 45.

Movement of the piston 17 to the right will cause clockwise rotation of the bell crank 95, as shown in Figure 2A, thereby pulling the cable 103 downwardly, moving lever 104 in a counter-clockwise direction, and displacing the lower end of the lever 107 to the right and moving the slide valve plunger to the right to its neutral position when the proper pitch has been attained.

When the control lever 110 is moved counter-clockwise, a reverse operation takes place. The lever 107 is moved in a clockwise direction and the slide valve plunger 108 is moved to the right. As a result liquid flows through the pressure line 47 into chamber 115 and from the latter into chamber 118 and through the conduit 50, passage 55 and conduit 60 into the right-hand end of the cylinder 14 and the left-hand end of the cylinder 15, thereby moving the pistons away from each other and changing the pitch of the blades 11. The liquid at the opposite ends of the cylinders flows through the conduit 66 and the passage 79 and conduit 49, chambers 116 and 119 into the return line 51 and into the reservoir 45.

Movement of the piston 17 to the left causes counterclockwise movement of the bellcrank 95, rotating the lever 104 clockwise in the proper direction to bring the slide valve back to its neutral position, as shown in Figure 3.

While an automatic follow-up system is described herein for regulating the pitch of the propeller, it will be understood that the cable 103 can also be connected to a pitch indicator and the valve 48 may be manually operated and the pitch controlled by reference to the indicator.

The above-described system is susceptible to considerable modification, particularly in the kind of motor used for varying the pitch of the propeller blades and in the number and arrangement of the blades on the hub. Accordingly, the forms of the invention described herein should be considered as illustrative and not as limiting the scope of the following claims.

I claim:

1. A variable pitch propeller system for a rotatable ship comprising a power-driven propeller shaft, a propeller hub fixed at one end to said shaft, a member supporting the other end of said hub for rotation relative thereto, propeller blades extending outwardly from said hub and rotatable relative thereto for varying their pitch, a cylinder in said hub, a piston reciprocable in said cylinder, a piston rod connecting said piston to said blades for rotating them relative to said hub in response to reciprocation of said piston, a source of hydraulic pressure, conduits extending from said source through said supporting member for supplying hydraulic pressure to said cylinder to reciprocate the piston therein, said conduits including a pair of concentric tubes supported by said member and extending into said piston rod, said tubes being non-rotatable and laterally movable relative to said member and slidably engaging said piston rod, and bearing means in said hub supporting said tubes substantially coaxial with said piston rod.

2. A variable pitch propeller system comprising a propeller having a hub, variable pitch blades thereon,

a propeller shaft supporting said propeller for rotation, a member movable in response to variation in pitch of said blades, and motion transmitting means connected to said member, said motiontransmitting means including an element movable axially with said propeller in axial displacement of the latter to maintain a fixed axially relation between said element and said propeller and sub stantially eliminate pitch varying movement of said member by axial displacement of said propeller.

3. A variable pitch propeller system comprising a propeller having variable pitch blades and an element reciprocable substantially axially of said propeller in response to variations in pitch of the blades thereof, a control member movable in response to reciprocation of said reciprocable element, motion transmitting means connecting said control member and said reciprocable element, said means including a lever having arms, means connecting one of said arms to said control member and another of said arms to said element, a pivot member supporting said lever, and means supporting said pivot member and movable with said propeller in all axial movements thereof.

4. A variable pitch propeller system comprising a propeller having a hub, variable pitch blades thereon, a reciprocable member connected to said blades and movable substantially in proportion to variation in the pitch of said blades, a propeller shaft connected to one end of said propeller hub for rotating it, a fixed member engaging and supporting the other end of said propeller hub, a member remote from said propeller and displaceable in proportion to variation in the pitch of said propeller blades, a motion transmitting element supported by said fixed member and movable bodily and rotatably relative thereto, means connecting said motion transmitting element to said remote member, means connecting said motion transmitting element to said reciprocable memher, and means for moving said motion transmitting element bodilyrelative to said fixed member in response to axial displacement of said propeller relative to said fixed member.

Meredith Mar. 27, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,931,443 April 5 1960 Lennart Anders Pehrsson It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 58, for "simplifier" read simplified column 5, line 56, strike out "rotatable" and insert the same after "a" and before "power-driven" in line 57 same column.

Signed and sealed this 13th day of September 1960',

(SEAL) Anest:

KARL AXLINE ROBERT WATSON Attesting Officer Commissioner of Patents 

